Collapsible tube and cap assembly and method of effecting the same



Nov. 14, 1933; A. w. PAULL El AL COLLAPS IBLE TUBE AND CAP ASSEMBLY ANDMETHOD OF EFFECTING THE SAME Filed Dec. 24, 1952 Patented Nov. 14, 1933UNITED STATES PATENT OFFICE Archibald W. Paull and John A. McGinnis,Wheeling, W. Va., assignors to Wheeling Stamping Company, Wheeling, W.Va., a corporation of West Virginia Application December 24, 1932 SerialNo. 648,816

3 Claims.

This invention relates to containers and closures therefor, and moreparticularly to containers formed of extruded soft metal such as arecommonly used for tooth paste, shaving cream,

5 and the like, and which are referred to generally as collapsibletubes.

The ordinary collapsible tube comprises an elongated tubular body of athin flexible nature terminating at one end in-a shoulder which has athreaded neck of smaller diameter than the tube projecting therefrom,the shoulder and neck being relatively heavier so as to resistdistortion. The neck is externally threaded, and is closed by a capwhich is screwed onto the threaded neck and which usually has a corkliner in order to efiectively seal the tube. These tubes are usuallyfilled under pressure by filling machines from the end of the tubeopposite the capped end, the large end of the tube subsequently beingsealed, and

it is very important in this filling operation that the cap shall bequite tight, as otherwise the contents of the tube leak out around thecap and spoil not only the appearance of a particular container wherethe cap is loose, but deposit -material on the filling machine whichsubsequently is transferred to other tubes in the process of filling,necessitating that the machine be stopped. The constituents of suchtubes, moreover, are frequently of an extremely oily nature,

or other volatile constituents, either of which have to be tightlysealed.

For this reason it has heretofore been considered necessary to provide acork in the caps for such tubes, this corking operation being a separatemanufacturing step in the making of the cap, and the caps have to betightly screwed onto the tubes in order that the cork'will be forcedtightly against the end of -the tube and prevent leakage. I a

In the formation of such tubes the tube is first extruded from a blankwithout threads on J the exterior of the neck and without the passageway through the neck being open at the .end of the tube. The tube issubsequently trimmed to remove metal from the end of the tube to open upthe passageway through which end the neck is threaded. According to thepresent invention, the tube is made in the usual way through the step oftrimming and threading the neck.

The present invention, however, contemplates the use of a special caphaving an outer portion which engages the threaded neck of the tube, andan inner portion which enters the opening in the neck of the tube and isforced by deforming the metal in the neck into a tight sealing relationwith the metal, eliminating any requirement for cork in the cap.Preferably the interior plug is threaded, and the application of the capto the tube causes a thread to be cut by such plug on the interior ofthe tube. Since the chasing of the 60 thread on the inside of the neckis effected by the application of the cap to the outside of the tube,the threads on the inside and outside of the neck stay in properrelation to one another, and the use of delicately adjusted machineryfor simultaneously chasing the threads on the inside and outside of theneck is eliminated, and there does not have to be any special relationbetween the point where the thread for that portion of the cap whichengages the outside of the neck begins with reference to the point wherethe thread on the plug portion of the cap begins. Furthermore, bycausing the thread on the plug to chase its own thread on the inside'oftheneck, a closer and more effective sealing is secured than if thethread on the inside of the tube were independently chased. I

The invention may be readily understood by reference to the accompanyingdrawing, in which:

Figure 1 represents a longitudinal section of a collapsibles tube after.it has been extruded and before it'has been trimmed or threaded;

Figure 2 is a similar view representing a section through the tube afterit has been trimmed and the outside of the neck threaded;

Figure 3 is a view similar to Fig. 2 after the cap has been applied tothe tube;

Figure 4 is a view similar to Fig. 3 showing the manner in which theinterior of the neck has been threaded by the application of the cap,the cap being removed in Fig. 4; and v Figure 5 is a section through thecap separate from the tube.

Referring to Fig. 5, the cap is of the conventional shape, comprising abody 2 having a laterally projecting fiange portion} which can beconveniently gripped, and a skirt portion 4 which is internally threadedfor application to the threads on the neck of a collapsible tube.Centrally positioned inside the skirt 4, and formed integrally with thebody of. the cap, is a central plug 5, this plug preferably being shapedin such a way that when the cap is screwed onto the neck of the tube theplug will force itself into seating relation or sealing relation withthe soft metal forming the interior of the neck of the tube. Preferably,the plug has external threads 6 for effecting this result. The cap maybe formed of the same material as the tube, that is,

' a1 bran new tin and antimonypor inthe ufacture of collapsible tubes,in that preferably, it is formed'of bakelite or some other the thread onthe inside 02 the neck is simul-= terial slightly harder than thematerial of: taneously efiected with the application of the which thetube is formed. cap to the tube, and the thread on the exteriorReferring to Fig.1, thecollapsible tube is first or the neck provides.the lead through which the formed with an extruded thin ductile body Ihavplugbn the interior of the -cap cuts the threads in in a heaviershoulder portion 8 and a neck porproper relation to the threads on theexterior of tion' 9, the end of the passageway through the the tube. Aneck being sealed as indicated at $10. The caps, particularly it formedof bakelite, In the usual course of manufacture, which is can be cheaplymolded with the threads on them, followed withthe present invention, theend of as will be readily understood by those skilledin the tube istrimmed to remove the obstruction the artoi working bakeli and the capischeaper l0, and a thread 11 is rolled or otherwise "chased tomanufacture and r uires fewer operations onto the, exterior of the neck.The cap 2 is then than the ordinary cap now commonly provided in appliedto the neckf- The skirt portion 4 is which a cork insert is positionedon the inside of longer than the plug portiont, so that the thread thecap.v At the same time, the cap forms a more on theskirt starts toengage the thread on,the emcient seal,flrst, because it does not haveneck before the plug enters the passage in the to: be screwed fully homein order to eii'ec neckof the tube. Howev'en'asthe cap is screwed sealthe end of the tube; and secondly, because home, the Pl turning andforcingits way down there is an actual interfitting of the sealing partsinto the neck of the tube is brought into a tight of the cap andtubewhich prevents leakage of sealing relation with the interior of theneck the contents of the tube.

of the tube. For instance, by usingthreads as i We claim: v

indicated at 6, these threads cut a shallow thread 1.- The combinationwith a collapsible. tube on the inside of the neck of thetube by means,formed of a soft pliable metal and having an ex- 109 of which a verytight'and effective sealing relateriorly threaded neck, of a cap havingan in tion .between'the tube and the cap is brought teriorly threadedskirt" engagin the threaded a about, and sealing relation exists evenneck of the tube and having a central plug elethoughthe cap should notbe turned all-the way ment of less length than the skirt and adapted tom will'he seen from the ioregoing'descripm home onthe threaded neck.When the cap is enter the neck of the tube, said plug having removed, asshown in 5, the interior. of'the" threads on the exterior thereof, thediameter or 'neck'will disclose the shallowthread which has the plugbeing such that the threads on the exbeenc'ut orchased into it by theplug portion 5 terior thereof will chase threads onthe interior ofthecap. I v oi the neck of the tube.

As hereinbefore indicated, since the thread on the inside of the neck isformed by the applicaformed of asbft pliable metal and having an extion'of the cap to the threaded exterior of the terio'rly threaded neck, ofa "cap of relatively tube, the" threads onthe inside and outside al-"hardermaterial having an interiorly threaded ways bear the pr perrelation with, respect to engaging the threaded neck or the tube and'each other and withrespect to the threads on the having a central plugelement thereon adapted t6 portions 4 and 5 0f that particular, cap;More-- enter the neck of the tube, said central plug beover, by formingthe thread on the inside of the ing externally threaded and adapted toce tube by the action of the plug 5, a tighter seal is threads. on theinterior of the neck of the tube obtained than: ii. the thread'wereindependentlyw whenthe cap is screwed onto the tube. formed on .theinside of the neck. "By having a 3. The combination with a collapsibletube 12g cap which is of slightly harder material than the formed of asoft pliable metal and having an exmetal of whichth tube is formed, athread is teriorly threaded neck, of a cap of relatively cut into theinside of the neck more efiectively harder material having an interiorlythreaded than where the plug is of asofjt meta-Land the skirt engagingthe threaded neck of the tube and. threads 6 could be mutilated,although our inhaving a central plug element thereon adapted ventioncontemplates either arrangement. Obvi to enter the neck of the-tube,said central plug ously, alsb, instead of forming threads on the beingexternally threaded-and-adapted to chase .inside'of the. neck of thetube, the plug nay disthreads on the interior of the neck of the tubeplace the soft metal'of-vthe. neck of the tube in when the cap isscrewed onto the tube, the plug other ways to efiect a tight-seal,although a thread. being of less length than the 'interlorly threaded134} is obviously preferable because of the tighter seal smrt. Vwhichiteflects.

um, inveniidn contemplates a new pd 2.- The combination with acollapsibleztube 1m

